Vegetal fibres as fat replacers for bakery products

The preference towards low-calorie products is constantly on the rise, and touches all food sectors: dairy, meat and derived products, breakfast range, fruit-based products, beverages, confectionery. Bakery sector makes no exception. The quantity of fat, and its characteristics, are crucial for bakery products, in order to obtain desired features as softness, superficial crunchiness, and aromatic profile. However, in some cases and after careful formulation tests, it is possible to successfully substitute part of this fat with vegetable sourced fat replacers. This replacement often allows a double advantage: reducing the calorie count of the product, and enhance its “healthy” profile by adding beneficial substances such as fibres. Average consumption of fibres in the population is far away from daily recommended dose of 14 g every 1000 kcal consumed (1). Both advantages (reduced calories and fibre supply) can be highlighted on the packaging and on the nutritional label, with high appeal on consumers. Furthermore, fibres added into bakery formulations often give also technical and rheological advantages to the dough, e.g. improved water holding capacity, with consequent extended shelf life thanks to the lower humidity and softness loss over time. Besides these two advantages of fibres (healthiness and good texture properties), there is a third one: they can be often sourced from vegetables as by-products, so their cost should decrease over the next years. Some of the vegetal fibres that is possible to use in bakery products as fat replacers are the following.Cocoa fibres. Cocoa beans peels are by-products of the cocoa industry, and are a rich but presently underused source of fibres and antioxidants. They keep cocoa colour and flavour, therefore they are ideal as fat replacers for cocoa/chocolate based bakery products. These fibres have been used in partial substitution of vegetable oil in chocolate muffins (2): the oil substitution ranged from 0% (control test) to 75%. Muffins with high substitution percentages did not rise as the control during cooking, and were less pleasant during chewing, but no negative impact was found on softness.

Fruit purees. Apple puree is a by-product of apple juice production and is very rich in pectin (hydro-soluble fibre with gelling and thickening properties). It has been used as fat replacer for biscuits (3): the substitution of 30% of fat in biscuit dough with apple puree gave a finished product with higher internal moisture, softer texture and paler superficial colour. For sweet bakery products, it is also possible to use other fruit purees or by-products, among which plums (4) and peaches (5).Pulse and vegetables purees. Purees obtained from peas (6), beans (7) or chick peas (8) can be used as fat replacers, even in sweet bakery products as cakes. Pea puree has been used in substitution of egg yolk in chocolate cakes (brownies), with increasing substitution percentages up to 100%: final moisture content was higher, and other sensorial characteristics (colour, flavour, taste and aftertaste, overall liking) were acceptable up to a 75% substitution. In other studies, beans and chick peas have been used in partial substitution of cream cheese in cheesecakes, adding also thickening agents such as xanthan gum in order to obtain a final texture as close as possible to the original product: with substitution percentages up to 50% (chick peas) or 60% (white beans), the final cake has been considered acceptable. Some other studies used as fat replacers corn fibres (9) and potato pulp (10).